Real-time audio, such as speech or voice in a telephone conversation may be stored in the payload of one or more data packets and transmitted over a data network, such as the Internet. One standard protocol for packetizing real-time audio for transmission over a data network is the Real-Time Transport Protocol (“RTP”) (Request for Comments (“RFC”) 1889, January 1996) at http://www.ietf.org/rfc/rfc/1889.txt
A system that includes both an Internet interface and a high speed serial (HSS) interface may receive voice packet data or audio stored in the payload of a network packet from an Internet Protocol (IP) telephone through the Internet interface to be forwarded to a Plain Old Telephone Service (POTS) telephone through the HSS interface
In order to minimize the number of packets dropped (not delivered), the system may temporarily store voice packet data received from the data network in a queue prior to forwarding them to the POTS telephone via a telephone network. However, if the rate at which voice packet data is added to the queue differs from the rate at which the voice packet data is removed from the queue, the voice packet data that is stored in the queue may increase over time.
In real world scenarios featuring POTS telephones, network processors, the Internet and IP telephones many factors can contribute to queue overload conditions which may result in dropped voice packets. For example, in contrast to a dedicated connection provided by a telephone network, each network packet may travel on a different path over the data network. This may result in a large burst of network packets being delivered to the system over the data network in a short period.
The number of voice packet data stored in the queue may affect the quality of the telephone conversation. For example, if the queue stores a maximum of 16 voice packet data and each voice packet data is 10 milliseconds (ms); this represents 160 ms of voice packet data which is greater than the typical 150 ms end-to-end latency requirement for “toll quality” calls. Also, the quality of service may be further reduced because received data packets may be dropped if the queue is full.
Although the following Detailed Description will proceed with reference being made to illustrative embodiments of the claimed subject matter, many alternatives, modifications, and variations thereof will be apparent to those skilled in the art. Accordingly, it is intended that the claimed subject matter be viewed broadly, and be defined only as set forth in the accompanying claims.